Supporting a JS Engine is non-trivial. See React Native and Native Script. For example stacktraces etc. With C++ in both Android Studio and X-Code you can put

Supporting a JS Engine is non-trivial. See React Native and Native Script. For example stacktraces etc. With C++ in both Android Studio and X-Code you can put break points in the same IDE. With JS you would use the browser to debug JS code, and Android Studio and X-Code to debug the native code. That split can be annoying. I guess if the team that supports the JS engine is sufficiently large, i guess you can get more out shared JS code. The majority of the devs should be able to focus on JS development only. And a couple of specialists deal with "JS engine issues".